byNASA -- Animation courtesy NASA GSFC Scientific Visualization Studio, based on data from MODIS, Landsat 7, and Space Imaging's IKONOS. Still image copyright www.spaceimaging.com/ Space Imaging, Inc.
Satellite remote sensors view the Earth at many scales of space, ranging from global through continental, regional, and local--even observing details as small as one meter (three feet) across. These data enable scientists to study a wide range of phenomena that occur over these same scales of space, such as El Nino, droughts, storms, and flash floods. The above image shows the Hollywood sign above Los Angeles, California. It is the final frame in an... Topics: What -- Earth, What -- Terra, What -- Landsat 7, Where -- Los Angeles, Where -- California Source: http://earthobservatory.nasa.gov/IOTD/view.php?id=1387
byNASA -- Images and animation by Robert Simmon, based on data aqcuired by the landsat.gsfc.nasa.gov/ Landsat 7 Science Team Landsat data is archived and distributed by the <a href''http://landsat7.usgs.gov/ USGS EROS Data Center
Although it is now the largest desert on Earth, during the last ice age the Sahara was a savannah with a climate similar to that of present-day Kenya and Tanzania. The annual rainfall was much greater than it is now, creating many rivers and lakes that are now hidden under shifting sands or exposed as barren salt flats. Over several hundred thousand years the rains also filled a series of vast underground aquifers. Modern African nations are now mining this fossil water to support irrigated... Topics: What -- Earth, Where -- Morocco, Where -- Algeria, Where -- United States of America, What --... Source: http://earthobservatory.nasa.gov/IOTD/view.php?id=2237